Explosion Containment
Explosion Containment
(OP)
Question:
I have a 15 lb object, and I have a 3/8 thk steel plate.
If my object is a large hex nut with (B7-105 ksi yield) and my plate is A36 (36 ksi yield) supported in a steel frame.
Is there anyway to determine what velocity that the hex nut (or any other object) would need to be in order to penetrate the plate? {Hopefully, I will not have sharp pointed objects in the failure event- but I note that anti-tank ammo is sharp and they cut through some some impressive armor}
The plate will be used to contain a high pressure set-up in the event of a failure. I can think of nothing, equation wise, to work this out.
jackboot
I have a 15 lb object, and I have a 3/8 thk steel plate.
If my object is a large hex nut with (B7-105 ksi yield) and my plate is A36 (36 ksi yield) supported in a steel frame.
Is there anyway to determine what velocity that the hex nut (or any other object) would need to be in order to penetrate the plate? {Hopefully, I will not have sharp pointed objects in the failure event- but I note that anti-tank ammo is sharp and they cut through some some impressive armor}
The plate will be used to contain a high pressure set-up in the event of a failure. I can think of nothing, equation wise, to work this out.
jackboot





RE: Explosion Containment
I`m also sure that there is no way to know it without testing, there are bullets in the market that have quite different penetration, having the same speed and mass, and just different jacket thickness, so who knows, maybe there are some impact test for nuts out there, but who could find them? good luck.
RE: Explosion Containment
RE: Explosion Containment
It still begs the question "what constitutes overbuilding in your case?"
If you just want to play around with some numbers, maybe get an order of magnitude sense of what you're dealing with:
- calculate delta enthalpy of the fluid in your "pressure vessel"
(total enthalpy, not specific enthalpy)
- equate that to the kinetic energy of the postulated "projectile"
- equate that to the strain energy of the impacted plate
* use something like the yield (or shear) strength
times the volume of deformed plate
* in effect, solve for the volume of plate required.
I don't suggest that the above be used as a design basis, but I think that you might, as I said, get an order of magnitude sense of things.
RE: Explosion Containment
I'll try typing it here:
Min perforation velocity Vxn
Omega = Plate density/ Projectile density = rhop/rhos
Cp,Cs = acoustic wave velocities in projectile & plate
eta = dynamic shear constant = 1.76x10^5psi in article
phi = [rhop*Cp +rhos*Cs]/[rhop*Cp*rhos*Cs]
T = plate thk
d= projectile dia
L =projectile length
here we go:
Vxn = [4*omega*T^2*phi*eta/(L*d)]{1+sqrt([(L+omega*T)/(omega*T)]*(1+(d/(4*rhos*T*eta*phi^2)))]}
they also give a few other formulas for pointed projectiles & oblique angles
the article should be @ nearest engrg college library
RE: Explosion Containment
That looks like what I need.
However, what does the Vxn equate to?
V=velocity?
n=angle(in radians)?
Please let me know.
jackboot
RE: Explosion Containment
C's [speed of sound] are in fps, too
rho's [density] are in (in-sec^2)/in^4
dim's in inches
RE: Explosion Containment
jackboot
RE: Explosion Containment
I've done a lot of hydrostatic and gas pressure testing and the enclosure is usually made of something flexible, chain mail or some other form of mesh. The suppliers of this stuff should be able to provide you performance data on their product, even if its only - our stuff will stop a 308.
RE: Explosion Containment
You are correct. We have looked at the situation and I have gone and "shot-up" two different grades of steel plate.
Further examination of the failure brought in a host of other problems. For instance, the oil will compress to a point that we will need .6 to .75 gallons extra oil for our test medium. This expansion plus the vessel being tested could potentially release 900,000 ft*lbs of energy.
So, looking at the situation we are going to intentionally weaken a portion of the assembly and make it fail in the test stand. This will be the only way to be sure.
Thanks for the help.
jackboot